This invention relates generally to a heat treating furnace and, more particularly, to a heat treating furnace of the type in which electric resistance heating elements are disposed inside of a work chamber to radiantly heat workpieces therein.
In some respects, the work chamber of the present furnace is similar to that disclosed in Bornor U.S. Pat. No. 3,456,935. Thus, the work chamber is defined within a walled enclosure having an outer wall and having radiation shielding packs attached to the inner side of the outer wall. Each shielding pack comprises a series of thin shields or plates made of temperature-resistant sheet metal and spaced inwardly from one another and from the outer wall of the chamber. The spaced shields serve to thermally insulate the chamber and to reflect radiation from the heating elements back to the workpieces in the chamber.
The electric resistance heating elements of the present furnace are attached to and are suspended from the outer wall of the work chamber by a plurality of hanger rods which extend inwardly through the radiation shields, the inner end portions of the hanger rods being connected to and being insulated electrically from the heating elements. Both the afore-mentioned Bornor patent and Jones U.S. Pat. No. 4,259,538 disclose hanger rods for supporting electric heating elements. In each instance, the hanger rods extend through holes in the outer wall of the chamber and are anchored by nuts located in and closing off the holes.